On 11/21/22 12:57, Pingfan Liu wrote:
Sorry that forget a subject.
On Mon, Nov 21, 2022 at 7:54 PM Pingfan Liu <kernelf...@gmail.com> wrote:
Hello Powerpc folks,
I encounter an kdump bug, which I bisect and pin commit 174db9e7f775
("powerpc/pseries/pci: Add support of MSI domains to PHB hotplug")
In that case, using Fedora 36 as host, the mentioned commit as the
guest kernel, and virto-block disk, the kdump kernel will hang:
The host kernel should be using the PowerNV platform and not pseries
or are you running a nested L2 guest on KVM/pseries L1 ?
And as far as I remember, the patch above only impacts the IBM PowerVM
hypervisor, not KVM, and PHB hotplug, or kdump induces some hot-plugging
I am not aware of.
Also, if indeed, this is a L2 guest, the XIVE interrupt controller is
emulated in QEMU, "info pic" should return:
...
irqchip: emulated
[ 0.000000] Kernel command line: elfcorehdr=0x22c00000
no_timer_check net.ifnames=0 console=tty0 console=hvc0,115200n8
irqpoll maxcpus=1 noirqdistrib reset_devices cgroup_disable=memory
numa=off udev.children-max=2 ehea.use_mcs=0 panic=10
kvm_cma_resv_ratio=0 transparent_hugepage=never novmcoredd
hugetlb_cma=0
...
[ 7.763260] virtio_blk virtio2: 32/0/0 default/read/poll queues
[ 7.771391] virtio_blk virtio2: [vda] 20971520 512-byte logical
blocks (10.7 GB/10.0 GiB)
[ 68.398234] systemd-udevd[187]: virtio2: Worker [190]
processing SEQNUM=1193 is taking a long time
[ 188.398258] systemd-udevd[187]: virtio2: Worker [190]
processing SEQNUM=1193 killed
During my test, I found that in very rare cases, the kdump can success
(I guess it may be due to the cpu id). And if using either maxcpus=2
or using scsi-disk, then kdump can also success. And before the
mentioned commit, kdump can also success.
The attachment contains the xml to reproduce that bug.
Do you have any ideas?
Most certainly an interrupt not being delivered. You can check the status
on the host with :
virsh qemu-monitor-command --hmp <domain> "info pic"
Thanks,
C.
